Fasting isn’t just skipping dinner—perhaps it’s even healthy for your gut and overall body. Scientists analyzed 31 animal and human studies to examine how the various forms of fasting affect the gut microbiome—and, more generally, metabolism and health.
What They Found:
- More beneficial bacteria: Fasting led to increases in beneficial gut bacteria including Akkermansia muciniphila, Bifidobacterium, and Faecalibacterium prausnitzii—all of which have been linked to decreased inflammation and better gut barrier function.
- More microbial diversity: Fasting increased the diversity and balance of gut bacteria, linked with better metabolic health and stress tolerance.
- More gut-friendly molecules: Molecules like short-chain fatty acids (SCFAs)—which have a central role in digestive and metabolic health—increased during fasting.
Types of Fasting Examined:
- Time-restricted feeding (e.g., 16:8 daily fasting window)
- Alternate-day fasting or adjusted caloric restriction
- Long-term fasts similar to those found in the Buchinger regimen or Ramadan fasting
Physiological Effects Encountered:
- Weight and metabolic benefits: Subjects had weight, blood pressure, blood sugar, and lipid decreases.
- Immunological effects: Certain regimens of fasting allowed for better production of molecules that boost immune function and reduce inflammation.
- Individual differences: Not all forms of fasting produced the same effect—outcomes were different depending on baseline diet, length of fasting, and the individual’s gut microbiome composition.
Why Further Research Matters:
Many of the studies varied considerably in design, population, and how the fasting was done. While findings are promising, more standardized human trials with longer follow-up are needed to confirm these benefits—particularly across differing age ranges, diets, and life styles.
Bottom line: Fasting can potentially rewire your gut microbiome for weight control, metabolic health, and reduced inflammation. But the effects are not universal and are determined by your individual biology and method of fasting.
Full text can be found in: Sumel Ashique, Biplab Debnath, Naheed Mojgani, Mohd. Tariq, Tanweer Haider, Eman Shorog, Sabina Yasmin, Anas Islam, Himanshu Sharma, Md Sadique Hussain, Ayush Madan, Tabarak Malik, Mohammad Yousuf Ansari, Gut microbiota modulation and health benefits of various fasting regimens, Current Research in Biotechnology, Volume 10, 2025, 100311, https://doi.org/10.1016/j.crbiot.2025.100311